It's been called “sustainability” or “designing for the environment.” Still others use terms such as “holistic building” or “environmental engineering.” Regardless of the descriptor, the influence of environmental issues on the choice of construction materials has intensified in recent years among architects, engineers, life cycle practitioners and building materials manufacturers.

Due to adoption by some state and local municipalities and federal government agencies, environmental issues are growing in importance and visibility. Requests for information on the environmental attributes of concrete are rising. With these trends in mind, Skokie, Ill.-based Portland Cement Association (PCA) introduces Concrete: Sustainability and Life Cycle (CD033), a CD-ROM collection of research and analysis from 1994 through 2002 that sets the record straight on the environmental characteristics of concrete and concrete materials and provides contextual results of concrete's impact on the environment.

The centerpiece of this new resource is environmental life-cycle assessment (LCA) — the analysis of a product or service from “cradle to grave” that begins with a life-cycle inventory (LCI). LCI evaluates a product's impact on the environment through the quantification of energy consumption, materials consumption, and emissions and residuals.

The second phase is characterization — a process of classifying the inventory data into impact categories, such as global warming potential, solid waste production and resource depletion. The final phase is impact assessment, which assigns values to the relative importance of the impact categories.

PCA commissioned four research groups to provide briefing papers on the issues, practices and debates in the sustainable development communities. In addition, a series of reports on the importance of addressing LCA and an evaluation on reducing CO₂ emissions in the manufacture of cement is included. Issues such as the use of fly ash in concrete encompass the next group of research findings and reports. Another report evaluates the LCI of 11 different portland cement concrete mixes.

RESIDENTIAL

A key component in the increasing popularity of concrete homes is their energy efficiency, and a report on the use of concrete in residential applications as it relates to sustainability and life cycle costs is included on the CD. The report evaluates concrete homes built with insulating concrete forms (ICFs) and standard and lightweight concrete masonry. The studies showed similar LCIs for concrete homes compared to other materials. However, in all cases the energy required for manufacturing cement and constructing the concrete, masonry, mortar, grout and stucco portions was less than 1 percent of the total life-cycle energy use for the house. Household energy use for heating, cooling and other uses dominates the total life-cycle energy use.

Homes built with insulating concrete forms (ICFs) used 5 to 10 percent less occupant energy and reduced HVAC system capacities 15 to 20 percent versus wood frame and masonry homes. ICFs fared better than the competition with regard to impact indicators in each category.

PAVEMENTS

The research concludes with an evaluation of cement-based pavements beginning with the six environmental impacts of portland cement concrete (PCC) and asphalt cement concrete pavements. In this study, the researchers evaluated the effects of pavement color on the microclimate; the artificial light required of pavements at night; the effect of pavements on vehicle fuel consumption; the inclusion of waste and recycled materials in pavement; the potential to recycle pavements at the end of their useful life; and the costs during construction, maintenance and reconstruction.

The comparison of collector and highway roads constructed with asphalt versus concrete showed that the energy used to manufacture the materials, and construct and maintain the roads was 25 to 40 percent less for PCC compared to asphalt. A second study compared actual use of fuel for heavy trucks in which PCC pavements demonstrated improved fuel consumption by as much as 11 percent.

The data on Concrete: Sustainability and Life Cycle (CD033) is searchable through the CD-ROM's Table of Contents, Abstract and Index. The CD costs $75 and can be ordered online at www.cement.org/lifecycle or by phone at 1-800-868-6733.